Dasher is like an arcade game: `Attack of the killer alphabets', perhaps.
Financial Times, 5th February 2002.
Dasher is a zooming interface. You point
where you want to go, and the display zooms in wherever you point.
The world into which you are zooming is painted with
letters, so that any point you zoom in on corresponds to
a piece of text. The more you zoom in, the longer the
piece of text you have written. You choose what you write
by choosing where to zoom.
In the example to the right, the user is writing "Hello,_how_are_you?".
To make the interface efficient, we use the
predictions of a language model to determine how
much of the world is devoted to each piece of text.
Probable pieces of text are given more space,
so they are quick and easy to select. Improbable
pieces of text (for example, text with spelling mistakes)
are given less space, so they are harder to write.
The language model learns all the time: if you use a novel
word once, it is easier to write next time.
A big advantage of Dasher over other predictive text-entry interfaces
that offer word-completions to the user
is that it is mode-free: the user does not need to
switch from a writing mode to an "accept-model-predictions" mode.
Another advantage is that it is easy to train the model
on any writing style: simply load up an example
file, then write away!